The invention generally relates to tubular connecting devices for making and breaking connections in conventional threaded tubulars. More particularly, the invention relates to a mechanical torque testing apparatus and method for making up tubular connections to be inserted into the annulus of a large diameter tubular.
Tubular members, such as drill pipe, tubing pipe and casing used in oil and gas exploration and production are normally threaded together at their ends. Drillers have long known that the amount of torque applied in xe2x80x9cmaking upxe2x80x9d the joint is critical. Tubulars torqued at a sub-optimal level will not provide the necessary fluid tight seal across the made-up connection to allow the pipe to back-off in the annulus during drilling operations. When excessively torqued, the tubulars can result in costly damage to the connection members from stripped, or otherwise damaged threads. Furthermore, it is believed that over-torqued, and therefore over-stressed, tool joints can to lead to premature failure of the connections.
Additionally, because non-ferrous tubulars are increasingly being used in horizontal drilling operations, make-up torque problems can occur as a result of their differences in strength and various material properties with respect to traditional steel pipe. The rig worker that is in the practice of torquing various alloys and configurations of oilfield tubulars must be able to accurately apply a desired torque to each connection that is made-up. Merely xe2x80x9ceye-ballingxe2x80x9d the amount of torque that is applied to a tubular connection is no longer a prudent practice among modern rig workers and reliable torque readings for each connection are important for such operations.
Traditionally, various devices and methods have been used to make-up and break-out threaded rotary connections in oilfield service. These prior-art methods include using the rotary table with pipe slips in conjunction with various pipe tong and top drive assemblies. Unfortunately, these systems utilize equipment that are bulky and difficult to manipulate and manage on a rig floor. Also, certain applications require the insertion of tubulars inside the bore or annulus portion of a drill stem or bottom hole assembly (BHA) to perform specialized tasks including, for example, sand packing a filter screen assembly. In order to perform these tasks, much smaller tubular components must be utilized to fit in the central bore of a drill string or into the annular space between the outer diameter of the drill string or BHA and the inner diameter of the well casing. These smaller tubulars require much less torque to properly make-up their connections so traditional means of torquing, for example, hydraulic tongs, produce torques too high to be used safely. Traditional means for dispensing torque are designed primarily for heavier duty tubulars such as drill string, and casing. As a result, there is a need in the industry for a torquing device and method that can accommodate smaller rotary tubular connections and dispense accurate torque loads thereto.
The apparatus of the present invention overcomes these problems by disclosing a compact system to be used to make-up and test the torque applied to a joint of small-diameter pipe on the rig floor all the while holding a larger diameter pipe to facilitate the insertion into the annulus thereof.
The present invention includes an apparatus for making up a smaller diameter tubular member by threading joints together to their recommended torque while securely and safely holding a larger diameter tubular or bottom hole assembly in rotary slips. An embodiment of the apparatus for connecting oilfield tubulars includes: a furcated or C-shaped base providing a longitudinal passage therethrough which may be moved on a rig floor over the upper end of a tubular or bottom hole assembly being held by the rotary slips; a longitudinally telescoping stop tower attached to the base which can act as a fulcrum for measuring the torque applied to a second tubular being inserted within the annulus or bore of the tubular or bottom hole assembly being held in the rotary slips: an adjustable plate connected to said base for centralizing a tubular or bottom hole assembly in the center of the longitudinal passage of the base; a stripping plate attached by an attached pipe collar to the top of said drill string; a bowl assembly set upon the stripping plate providing a means for holding a smaller diameter or second tubular in a set of pipe slips by seating in said bowl assembly; a torque arm releasably connected to the smaller diameter tubular being inserted in the drill string extending to a load cell mounted on the telescoping outrigger of the base, so that when torque is applied to the smaller diameter second tubular member, the torque may be readily determined by the operator on the rig floor.